1. Technical Field
The present invention relates to a sheet folding apparatus for folding a sheet fed from an image formation apparatus to feed to a post-processing apparatus, and more particularly, to improvements in the jam handling mechanism to remove a sheet jam.
2. Description of the Related Art
Generally, this type of sheet folding apparatus has been known as an apparatus for folding a sheet with an image formed thereon by an image formation apparatus such as a printing press, printer apparatus and copier in a predetermined fold position to perform finish processing.
For example, Japanese Patent Application Publication No. 2009-018494 proposes an apparatus in which a sheet folding apparatus is coupled to a sheet discharge outlet of an image formation apparatus, folds a sheet with an image formed for filing, and carries the sheet out to a subsequent binding processing apparatus (post-processing apparatus). In the document, the sheet folding apparatus is coupled to the sheet discharge outlet of the image formation apparatus, and a bookbinding processing apparatus is disposed on the downstream side of the sheet folding apparatus.
Not only such a system configuration in Japanese Patent Application Publication No. 2009-018494, it is known widely that part of an apparatus casing is configured to be openable and closable to open and close the path when a paper jam occurs in the transport path of sheets in the sheet folding apparatus. Such a structure is generally configured by hinge-coupling part of a casing to an apparatus frame to be openable and closable and exposing the sheet transport path to the outside with the casing opened.
Japanese Patent Application Publication No. S61-002637 discloses a post-processing apparatus and proposes a jam open/close mechanism for hinge-coupling one side end edge (for example, the apparatus left side end portion) orthogonal to the sheet transport direction in an apparatus for collating and collecting sheets fed from an image formation apparatus to perform binding processing.
More specifically, first, such a sheet folding apparatus as described above is known in Japanese Patent Application Publication No. 2009-018494, etc. The sheet folding apparatus is disposed between the image formation apparatus and the post-processing apparatus, and folds an image-formed sheet to feed to the post-processing apparatus. The sheet folding apparatus is provided with a transport path for carrying a sheet from a carry-in entrance to a carrying-out exit without performing folding processing on the sheet, and a folding processing path for performing the folding processing on a sheet to feed to the carrying-out exit.
Then, in the sheet folding apparatus disposed between the image formation apparatus and the prost-processing apparatus, an apparatus configuration is required which is small and compact as possible, and particularly, slim in the sheet feed direction. It is natural because the installation space of the entire system is reduced (narrowed).
Therefore, previously, the applicant of the invention conceived slimming the folding processing mechanism by placing a folding processing path for performing folding processing on a sheet fed from the carry-in entrance in the direction for crossing a transport path (through-pass path) for carrying a sheet from the carry-in entrance to the carrying-out exit without performing the folding processing, and filed the patent application (Japanese Patent Application No. 2009-291375). When a sheet jam occurs in such an apparatus configuration, the need arises for opening the transport path to remove the jam.
The inventor of the invention arrived at the idea that it is possible to retrieve jam sheets occurring in both paths, by dividing the configuration into two upper and lower portions with the through-pass path as a boundary and opening and closing the upper unit in the path configuration in which the folding processing path is disposed in the direction for crossing the through-pass path. Concurrently therewith, the inventor arrived at the idea that it is possible to reduce the size of the entire system without the image formation apparatus and the post-processing apparatus located at the front and back and the open/close space interfering with one another, by providing the upper unit with open/close motion around the hinge in the side end portion (apparatus rear side end portion) parallel with the sheet transport direction with respect to the lower unit.
Further, second, in Japanese Patent Application Publication No. S61-002637, when a sheet is jammed in a press-contact portion in a pair of folding rollers, the sheet transport mechanism is opened, and the sheet is pulled out with the sheet nipped between the rollers. Therefore, in a thin sheet or a sheet becoming wrinkled by the jam, part of the sheet may be broken and remain inside the apparatus. Alternately, in pulling out the sheet nipped between the rollers inside the apparatus, the operator may be injured.
Then, the inventor of the invention arrived at the idea that it is possible to release a plurality of press-contact portions by withdrawing a roller positioned in the center, and at the same time, restore to the original engagement relationship reliably in a folding roller mechanism in which a plurality of press-contact rollers is disposed around the roller positioned in the center.